Californians who try to contact their state senator over the next two years may be surprised to find out they don't have one.

It's a quirk that is due to the once-a-decade redrawing of Senate district lines that leaves some areas - and more than 2 million California voters - without an elected representative in the upper house of the Legislature, while other areas have two senators.

In the Bay Area, Marin County is without representation, while people in San Francisco and much of San Mateo County now have two senators they can call for assistance. The phenomenon is statewide, including in both urban and rural areas.

In all, 2.2 million voters now lack a senator while 1.8 million have double representation, according to a report from Political Data Inc., a firm that tracks voter information.

'Caretaker' senator

Senate leaders are meeting this week to determine who will be responsible for those areas without representation and assign a "caretaker" senator that people can contact for assistance.

It is likely that state Sen. Noreen Evans, D-Santa Rosa, will be responsible for Marin County, and her office has been "absolutely inundated" with calls from residents and local elected officials there, said Teala Schaff, Evans' spokeswoman.

"Marin is probably the most engaged citizenry in the state as far as regular voters and actively engaged voters," Schaff said.

Nancy Hall Bennett, a public affairs manager for the League of California Cities in Marin County who is helping local officials connect with Evans' office, said people see a positive side to the situation as they still have a relationship with state Sen. Mark Leno, D-San Francisco, who represented the county until his district was redrawn.

"He's not gone. While he doesn't represent them officially, they don't feel like they have been left in the lurch," Hall Bennett said. "It can be looked at either way. I think our folks really look at it as a positive."

The cause of the situation is that state Senate elections are staggered, with half of the 40-member body on the ballot every two years. In November, only the odd-numbered districts were on the ballot, so places like Marin County that were moved into even-numbered districts via redistricting have to wait two years before having a chance to vote for a senator.

When that happens in 2014, the county will be part of a massive district that stretches from the Golden Gate to the Oregon border, and it will be the first Senate election since 2008. The changing lines did not have the same effect on the Assembly, as every seat in the 80-person house is on the ballot every two years.

Overlapping areas

The changing lines combined with staggered elections can have the opposite effect, too. Now, both Leno and state Sen. Leland Yee, D-San Francisco, represent overlapping parts of the district in the western half of the city. Yee and state Sen. Jerry Hill, D-San Mateo, also represent overlapping areas of San Mateo County.

In 2014, the even-numbered district represented by Yee will move into the Sierra Nevada and parts of the Central Valley.

Staffers at the Capitol are working to update the state Senate website, and people living in unrepresented areas will be able to enter their address information and will be told who their caretaker senator is, said Sheron Violini, deputy secretary of operations for the state Senate Rules Committee.

That could take up to a week to complete, she said.

It's not clear whether those caretakers will see an increase in their office budget to help deal with the increase in constituents, but she said Californians should not worry about having adequate representation.

"I think it's our responsibility as public servants to reassure people that there is an avenue for them to express their voice or opinion," Violini said. "We have been actively working on this for months, and they will have a representative."